Racial, ethnic, and socioeconomic disparities in academic achievement remain a stubborn fact of schooling in the United States. National studies consistently show that the average non-Hispanic black student scores well below the average non-Hispanic white student on standardized tests of math and reading skills, as does the average Hispanic student. Likewise, the average student from a low-income family scores much lower on such tests than students from higher-income fami-lies. Considerable attention has been focused on achievement gaps, particularly the black-white achievement gap. Scholars and educators have suggested a number of possible explanations for these gaps, and policy makers, principals, and teachers have tried a range of remedies. As this chapter documents, however, the gaps persist despite these efforts. Moreover, our understanding of the causes and patterns of these achievement gaps is far from complete.